First-principles investigation of electronic and optical properties in wurtzite Zn<Subscript>1-x</Subscript>Mg<Subscript>x</Subscript>O

A first-principles study has been performed to evaluate the electronic and optical properties of wurtzite Zn<Subscript>1-x</Subscript>Mg<Subscript>x</Subscript>O. Substitutional doping is considered with Mg concentrations of x=0, 0.0625, 0.125, 0.1875 and 0.25, respectively. Mg incorporation can induce band gap widening due to the decrease of Zn 4s states. The imaginary part of the dielectric function shows that the optical transition from band edge emission decreases slightly with increasing Mg contents. The optical band gap also increases from 3.2 to 3.7 eV with increasing Mg contents from 0.0625 to 0.25. The calculated results suggest that relatively high Mg concentration is necessary for effective band gap engineering of wurtzite Zn<Subscript>1-x</Subscript>Mg<Subscript>x</Subscript>O. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2008